Adjustable crank



0d. 24, 1933. CROQM 1,931,861

ADJ US TABLE CRANK Filed March 8, 1930 i IO q I V INVENTOR. GUY C-ROOM. FT E,I BY W I ATTORNEYS ?atented Get. 24, 1933 ADJUSTLE CRANK Guy Groom, Lufkin, Tex, assignor to Lufkin Foundry & Machine Qompany, Lufkin, .Tex.

Application March 8, 1930. Serial No. 434,22ii

Claims.

My invention relates to pumping units and more particularly to the manner of securing the crank arm to the crank shaft in pumping units. In the construction of pumping units provision 5 must be made not only for the pumping of the well but for the repair of the parts of the pump and replacement thereof where wear occurs in the operation thereof.

It is necessary in connection with the pump to m provide means for withdrawing the pump rods and plunger and also the pump tubing when necessity for cleaning or repair occurs. For this reason the pumping units must be equipped with a hoist whereby the pump may be removed from s the well when necessity arises.

The pump and the hoist are both operated from one crank shaft and while the hoist is working the connection with the pump must be disengaged so that the crank shaft may rotate uniformly in the hoisting operation.

lit is an object of my invention to provide a connection between the crank shaft and the crank arm so that the crank arm may be disconnected from the shaft when desired.

I also desire to provide an adjustable connection between the crank arm and the shaft so that the position of the arm on the shaft may be changed from time to time to provide for wear on the driving gear connected therewith. his to be understood that in the pumping operation there is a working stroke and an idle or return stroke. Where the crank assumes a fixed position on the shaft the load of the pump comes on the driving gears connected with the crank shaft only on the working stroke and it is found that the gears con= nected with the driving mechanism wear on the portion'of the circumference where the load is taken. if, therefore, the angle of the crank arm on the shaft can be changed from time to time the wear upon the gears may be also shifted from one point on. the circerence to another and thus provide for a uniform wear upon the gears. By arranging the crank arm for adiust= merit to difierent positions on the shaft I am therefore enabled to produce a more uniform wear upon the driving parts of the mechanism.

With reference to the drawing herewith, Fig. l is a broken view illustrating the use of my improvement upon a pumping unit.

2 is a broken sectional view longitudinally of the crank arm illustrating the manner in which the crank arm is secured to the shaft.

3 is a side elevation of the crank arm, certain parts being broken away for greater clear Ali?) (Ci. 7M8) ness, the view being taken from the right of Fig. 2.

With reference particularly to Fig. 1 it will be seen that a pumping unit such as is ordinarily employed in pumping wells includes a walking beam I mounted for a rocking movement upon a Samson-post 2.- The forward end of the walking beam is connected to a flexible rod engaging means 3 by which the pump rod may be reciprocated. The opposite end of the walking beam is connected with a pitman d, which is connected at its lower end to a wrist pin 5 upon a crank arm 6 secured upon the crank shaft 7. The crank shaft 7 may be operated from connection with any source of power. Said shaft is connected by 7c means of a sprocket chain 8 to a hoisting drum 9 mounted upon the derrick platform 10. Said hoisting drum may be connected over the upper end of the derrick with a cable running downwardly for connection with the upper end of the pump rod when said rods are to be pulled from the well. My invention lies largely in the manner in which the crank arm 6 is secured to the crank shaft 7. As will be seen from Fig. 2 the crank shaft has secured thereon, at a point spaced w from the outer end. a drive disc ll. Said disc has on its outer face an inwardly tapered or beveled groove 12. Said groove is an annular groove extending around the disc spaced inward ly from the outer periphery of said disc. The 35 lower portion of said groove may be provided with notches or teeth 13, seen best in Fig. 3. This'disc is secured rigidly to the shaft and is keyed thereto, as shown at it. W

The crank arm 6 is mounted rotatably upon m the crank shaft 7. I may provide an inner bush ing 14' between said arm and the shaft to be replaced in case of wear. The inner face of the crank arm has thereon a ridge if, the sides of which taper outwardly and are shaped to fit within the groove 12 in the disc. The outer ends of the said ridge may be notched to engage within the teeth 13 in the disc. It will be noted that the beveled sides of the ridge 15 may be forced with a wedging fit into the groove 12 so as to 3% make a tight frictional engagement between the. two so that they may be locked together. The outer end of the crank shaft 7 is provided with a nut 16, which may be used to clamp the crank arm against the drive disc ii and hold the two nonrotatably together. This nut is shown as be= ing disposed in a recess in the crank arm so that the pitman rod connected to the pin 18 may be connected closely to the or arm.

The crank arm may be understood as being of ordinary construction, having openings 17 therein to receive the wrist pin 18. I have shown the crank arm as equipped with counterweights l9 adjustable along the sides of the crank arm to balance the weight of the load in pumping.

In the ordinary operation of my device during the pumping of the well the crank arm will be clamped tightly against the drive disc so as to be rotated with the crank shaft to operate the walking beam. The position of the crank arm upon the shaft may be changed from time to time by simply loosening the clamping nut 16 and moving the arm outwardly from the clamping disc and rotating it through a small angle so as to place the load at a different angular position on the shaft, this allowing the load to be received upon the shaft at different positions about the circumference of the shaft.

Further, when the hoist is to be used for raising the load of sucker rods or tubing from the well the crank arms may be entirely released from engagement with the crank shaft by loosen= ing the clamping nut 16 and moving the crank arm free of the drive disc so that the rotation of said disc will impart no motion to the crank arm but will allow the same to hang idly on the shaft during the use of the hoist.

The advantages of this construction will be obvious to those skilled in the art. The use of the crank shaft for hoisting operations may proceed unencumbered by any connection with the crank arm. Furthermore, the manner in which my crank arm may be adjusted at various positions relative to the shaft allows me to obtain a uni-' form wear upon the driving mechanism by which the crank shaft is rotated. I provide a simple and economical means whereby the crank arm may be secured to the shaft in such a manner that it may be easily adjusted or released therefrom.

What I claim is new is:

1. In a pumping unit for wells, a crank shaft,

earner.

a drive disc fixed thereon, the outer side of said disc having an annular groove therein, a crank arm rotatable on said shaft, an annular ridge on said arm shaped to fit within said groove, and

means to clamp said crank arm against said disc, said ridge engaging in said groove.

2. In a pumping unit for wells, a crank shaft, a drive disc fixed thereon, the outer side of said disc having an annular groove therein, a crank arm rotatable on said shaft, an annular ridge on said arm shaped to fit within said groove, inter== engaging teeth in said groove and on said ridge, and means to clamp said crank arm against said disc,said ridge engaging in said groove.

3. In a pumping unit for wells, a crank shaft, a drive disc fixed thereon, the outer side of said disc having an annular groove therein, a crank arm rotatable on said shaft, an annular ridge on said arm shaped to fit within said groove, and a nut on said shaft to clamp said crank arm fric= tionally against said disc in the manner de= scribed.

4. In a pumping unit for wells, a crank shaft, a drive member fixed thereon, a crank arm rotatable with respect to said shaft, annular tongue and groove portions on said crank arm and said member, and means to clamp said crank arm and said drive member positively together whereby they will rotate as a unit.

5. A crank arm for pumping units including a hub portion, an opening therein to receive the crankshaft, a recess in the face of said hub, a nut adapted to be threaded onto said crank shaft and be received in said recess, and means fixed on said shaft and adapted to rotate therewith and against which said crank arm is clamped by said nut, said nut being countersunk in said recess so that the pitman rod may be connected closely to said crank arm. GUY CROOM. 

